WIP on into_shape_clone

Author: bluss

src/impl_methods.rs

@@ -1929,28 +1929,48 @@ where
     {
         let (shape, order) = shape.into_shape_and_order();
         let order = order.unwrap_or(Order::RowMajor);
+        self.into_shape_clone_order(shape, order)
+    }
 
-        if size_of_shape_checked(&shape) != Ok(self.dim.size()) {
+    pub fn into_shape_clone_order<E>(self, shape: E, order: Order)
+        -> Result<ArrayBase<S, E>, ShapeError>
+    where
+        S: DataOwned,
+        A: Clone,
+        E: Dimension,
+    {
+        let len = self.dim.size();
+        if size_of_shape_checked(&shape) != Ok(len) {
             return Err(error::incompatible_shapes(&self.dim, &shape));
         }
-        let layout = self.layout_impl();
 
-        unsafe {
-            if layout.is(Layout::CORDER) && order == Order::RowMajor {
-                // safe because arrays are contiguous and len is unchanged
-                Ok(self.with_strides_dim(shape.default_strides(), shape))
-            } else if layout.is(Layout::FORDER) && order == Order::ColumnMajor {
-                // safe because arrays are contiguous and len is unchanged
-                Ok(self.with_strides_dim(shape.fortran_strides(), shape))
-            } else {
-                let (shape, view) = match order {
-                    Order::RowMajor => (shape.set_f(false), self.view()),
-                    Order::ColumnMajor => (shape.set_f(true), self.t()),
-                };
+        // Safe because the array and new shape is empty.
+        if len == 0 {
+            unsafe {
+                return Ok(self.with_strides_dim(shape.default_strides(), shape));
+            }
+        }
 
-                Ok(ArrayBase::from_shape_trusted_iter_unchecked(
-                            shape, view.into_iter(), A::clone))
+        // Try to reshape the array's current data
+        match reshape_dim(&self.dim, &self.strides, &shape, order) {
+            Ok(to_strides) => unsafe {
+                return Ok(self.with_strides_dim(to_strides, shape));
+            }
+            Err(err) if err.kind() == ErrorKind::IncompatibleShape => {
+                return Err(error::incompatible_shapes(&self.dim, &shape));
             }
+            _otherwise => { }
+        }
+
+        // otherwise, clone and allocate a new array
+        unsafe {
+            let (shape, view) = match order {
+                Order::RowMajor => (shape.set_f(false), self.view()),
+                Order::ColumnMajor => (shape.set_f(true), self.t()),
+            };
+
+            Ok(ArrayBase::from_shape_trusted_iter_unchecked(
+                        shape, view.into_iter(), A::clone))
         }
     }
 
@@ -1984,6 +2004,7 @@ where
         A: Clone,
         E: IntoDimension,
     {
+        return self.clone().into_shape_clone(shape).unwrap();
         let shape = shape.into_dimension();
         if size_of_shape_checked(&shape) != Ok(self.dim.size()) {
             panic!(